Thanks to The Mystical One for posting this on the forums.

http://www.gamefaqs.com/boards/937281-dragon-quest-ix-sentinels-of-the-starry-skies/57333492

From yab:
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I have some information on the regular game blue chests.
There are ranks for the regular game blue chests just like the grotto ones, however there are different ranks with different items.

First, here's the chest list.
If you need more information as to their locations, check this thread:
http://www.gamefaqs.com/boards/937281-dragon-quest-ix-sentinels-of-the-starry-skies/55969240

Num. [rank] location
01. [1] Angel Falls - Well
02. [1] The Hexagon - B1, take left stairs from L1
03. [2] The Hexagon - B1 left side after passing through B2
04. [2] Stornway - Stairs west of inn
05. [1] Stornway - Weapon shop
06. [2] Brigadoom - Outside, center
07. [2] Brigadoom - Northwest tower (go left from entrance)
08. [3] Stornway Castle - Treasure room, left chest
09. [2] Stornway Castle - Treasure room, right chest
10. [3] Quarantomb - L1, left one space, up one space
11. [3] Tower of Trades - 2F left
12. [3] Tower of Trades - 2F middle
13. [2] Tower of Trades - 2F right
14. [4] Tower of Trades - 4F
15. [3] Twyll Cave - Outside
16. [3] Twyll Cave - L2 center
17. [2] Dourbridge - North house
18. [3] Heights of Loneliness - 2F
19. [3] Heights of Loneliness - 7F
20. [3] The Bad Cave - 1F hideout, bottom
21. [2] The Bad Cave - 1F hideout, top
22. [3] The Bad Cave - 1F left side, plateau
23. [1] The Bad Cave - B1
24. [4] The Bad Cave - B2
25. [4] The Plumbed Depths - B1
26. [3] The Plumbed Depths - B2 right, right chest
27. [4] The Plumbed Depths - B2 right, left chest
28. [3] Gerzuun - east
29. [3] Gerzuun - inside well to west
30. [4] Gerzuun - high area (right lower)
31. [4] Gerzuun - high area (left upper)
32. [3] The Old School - B1
33. [3] Wormwood Creek - Item shop
34. [4] Bowhole - outside, southeast
35. [4] Bowhole - outside, east end, left
36. [5] Bowhole - outside, east end, right
37. [4] Bowhole - B1 southwest
38. [5] Bowhole - B1 northwest
39. [4] Bowhole - B2 southeast
40. [5] Bowhole - B2 northwest
41. [5] Bowhole - B3
42. [2] Upover - Item shop
43. [2] Upover - West house
44. [3] The Magmaroo - L1, outside
45. [3] The Magmaroo - Summit
46. [4] Gittingham Palace - L1 North, right
47. [4] Gittingham Palace - L1 North, middle
48. [5] Gittingham Palace - L1 North, left
49. [3] Gittingham Palace - L3
50. [5] Oubliette - B6
51. [4] Realm of the Mighty - L1 (in right door)
52. [4] Realm of the Mighty - L2
53. [4] Realm of the Mighty - L3
54. [4] Realm of the Mighty - Outside (from L4)
55. [5] Realm of the Mighty - L5
56. [5] Realm of the Mighty - L6
57. [5] Realm of the Mighty - Outside (from L6)
58. [3] Western Wormwood - well
59. [5] Tower of Nod - 1F
60. [5] Tower of Nod - 3F
61. [4] Tower of Nod - 5F
62. [5] Tower of Nod - 6F
(if I missed any, let me know)

Chest contents:
Rank 1: Medicinal herb (25%), Antidotal herb (20%), Moonwort bulb (10%), Holy water (10%), Chimaera wing (10%), Iron nails (5%), Sandals (5%), Cotton gloves (5%), Plain clothes (5%), 18G (5%)
Rank 2: Medicinal herb (15%), Antidotal herb (10%), Moonwort bulb (10%), Strong medicine (10%), Chimaera wing (10%), Angel bell (10%), Coagulant (10%), 52G (7%), Gleeban groat (5%), Paring knife (5%), Leather shoes (5%), Magic water (3%)
Rank 3: Iron nails (10%), Gleeban groat (10%), Magic water (10%), 240G (10%), Tortoiseshell (8%), Toad oil (8%), Mystifying mixture (7%), Strong medicine (5%), Evac-u-bell (5%), Strong antidote (5%), Gold bracer (5%), Resurrock (5%), Gleeban guinea (5%), Mini medal (5%), Sage's elixir (2%)
Rank 4: Cannibox (10%), Special medicine (10%), Mini medal (10%), Gleeban groat (10%), Magic water (10%), Finessence (5%), Ultramarine mittens (5%), Sorcerer's stone (5%), Gold rosary (5%), Iron ore (5%), Gleeban guinea (5%), Sage's elixir (5%), 525G (5%), Silver platter (5%), Aggressence (5%)
Rank 5: Mimic (10%), Panacea (10%), Mini medal (10%), Gleeban guinea (10%), Sage's elixir (8%), Prayer ring (5%), Einhänder (5%), 1000G (5%), Gleeban gold piece (5%), Agility ring (5%), Yggdrasil leaf (5%), Resurrock (5%), Strength ring (5%), Hephaestus' flame (5%), Gold rosary (5%), Reckless necklace (2%)

Pots, barrels, closets, etc. are treated just like blue chests with the exception that they don't have items every time.
Once the pot has been opened it won't have any items in it again until you restart, even if there wasn't an item.

There are 20 "ranks" of pots: Totals are in brackets []
Rank 1: [20%] 2G (10%), Medicinal herb (10%)
Rank 2: [30%] 5G (10%), Medicinal herb (15%), Antidotal herb (5%)
Rank 3: [30%] 2G (10%), 4G (10%), 8G (5%), 12G (5%)
Rank 4: [40%] Medicinal herb (12%), Antidotal herb (8%), 16G (5%), Moonwort bulb (5%), Evac-u-bell (5%), Chimaera wing (5%)
Rank 5: [50%] Medicinal herb (12%), Antidotal herb (8%), Moonwort bulb (5%), 48G (5%), Evac-u-bell (5%), Chimaera wing (5%), Angel bell (5%), Strong medicine (5%)
Rank 6: [40%] Cowpat (20%), Horse manure (20%)
Rank 7: [50%] Wing of bat (10%), Tortoiseshell (10%), Toad oil (10%), Lambswool (10%), Snakeskin (10%)
Rank 8: [50%] Strong medicine (10%), Special medicine (5%), Strong antidote (10%), Special antidote (5%), Magic water (5%), Sage's elixir (5%), Angel bell (5%), Mini medal (5%)
Rank 9: [40%] Gleeban groat (10%), 120G (10%), Resurrock (10%), Mini medal (10%)
Rank 10: [50%] Lava lump (5%), Fresh water (5%), Flurry feather (5%), Royal soil (5%), Ice crystal (5%), Thunderball (5%), Evencloth (5%), Brighten rock (5%), Resurrock (5%), Mini medal (5%)
Rank 11: [50%] Cotton gloves (20%), Cotton trousers (15%), Plain clothes (15%)
Rank 12: [30%] Sandals (15%), Pop socks (5%), Hairband (10%)
Rank 13: [50%] Leather shoes (15%), Boxer shorts (15%), Bandana (20%)
Rank 14: [50%] 2G (15%), 5G (15%), 10G (10%), 15G (5%), 30G (5%)
Rank 15: [30%] Plain clothes (10%), Wayfarer's clothes (5%), Silk robe (5%), Springtime skirt (5%), Leather hat (5%)
Rank 16: [50%] Medicinal herb (15%), Antidotal herb (10%), Moonwort bulb (10%), Holy water (5%), Chimaera wing (10%)
Rank 17: [25%] Silver bracelets (5%), Gold bracer (5%), Slime earrings (5%), Gold ring (5%), Bunny tail (5%)
Rank 18: [40%] Boxer shorts (10%), Cotton gloves (10%), Linen gloves (5%), Leather gloves (5%), Rubber gloves (5%), Mini medal (5%)
Rank 19: [30%] Leather dress (5%), Dancer's costume (5%), Garish garb (5%), Feathered cap (5%), Fur hood (5%), Leather kilt (5%)
Rank 20: [50%] 12G (20%), 40G (15%), 120G (5%), 240G (5%), Mini medal (5%)

Example listing:
Stornway:
Pot by weapon shop: 1
Pot by church: 2

Stornway cellar:
Pots (top to bottom): 2, 1, 3
Barrels left side (starting from closest): 2, 3, 1
Barrels right side: 2, 1

RNG manipulation, you can skip this if you don't care.

Like grotto chests, the contents are set when entering the room or exiting battle records.
They're based only on whatever the A table is at the time, timers are not used.
So we can use the map method to manipulate what's in these chests. It should be done before either entering the room they are in or you can go into battle records to reset the chest contents.
Moving NPCs and monsters will screw things up, so it's not a good idea to try this in dungeons or some town areas.
Some good areas are Stornway treasure room (2-3), Magmaroo (3), Gittingham Palace (4-5), etc.

The map method sets the seed and then advances AT +32. Doing battle records will increase AT at least by the number of chests/pots even if they've been opened before. (Some rooms use up additional AT, I haven't checked why)
For the Stornway cellar example, each BR advances AT +11.
The first few numbers determine the blue chests, then any pots/barrels/etc.
The formula is AT result ([0~32767]-1) x 100 / 32767, round down (or 0 if negative) = number from 0 to 99

Example with Stornway cellar when using "Granite Tunnel of Woe Lv. 1" and BRx1:
1: 45 -> Chimaera wing (rank 2 chest)
2: 88 -> Nothing
3: 82 -> Nothing
4: 21 -> 8G (rank 3 pot)
5: 30 -> Nothing
6: 6 -> 2G (rank 3 pot)
7: 69 -> Nothing
8: 68 -> Nothing
9: 23 -> Nothing (rank 1 pot)

You don't get much useful stuff from pots anyway. Even the blue chests aren't that great, but if you want to farm items from them you can use this web site:

tl;dr - website to get stuff from blue chests
http://www.yabd.org/apps/dq9/bluechests.php
Enter in a map seed, use the map method/BR whatever number of times, get stuff.